I'm guessing almost nobody is interested in making the interior more quiet, but still going to ask, has anyone done sound deadening to their F56/F55?

I didn't do mine yet because it was a lease, but now that I went through a lease buy-out and I know I'll keep the car for longer, I wanted to do sound deadening if I find some time in the future. Interior noise is worse than a 2014 CX-5, and Mazda is not that much of a quiet car either.

I already have some stick on pads (butyl sticky + aluminum layer) that I bought long time ago. I do need to order the rest of the stuff, and here's what I'm thinking of:

-Roxul Safe n Sound rock wool batt $48, to stuff in the rear cavities, and some other panels maybe -> edit: not a good idea
-Close cell foam (CCF) 48" x 0.125" x 4' $33 -> just for the two doors
-Mass loaded vinyl (MLV) layer 54"x25' $182
-HH-66 glue $25
-3M 77 adhesive spray $10
-UltraTouch Radiant Barrier 48" x 24' $61 -> for headliner and stuffing cavities
-2" x 4" Velcro Strips x 8 $15

I wonder whether the effort is going to be effective to reduce road noise. Depending on how hard to remove things, I might just end up doing the side panels and truck, or if it's super easy I want to do the floor and ceiling too.


edit: Some links for related information:
Tesla complete sound deadening
Sound deadener showdown
2nd gen Cooper 2 door thread
Genesis tear down

 

I did some small areas when upgrading speakers, no idea if it helped. What tires are you running? I think that is the biggest offender with these cars.

Wife F55 2016 is actually pretty quiet compared to my F56. I think it's tires and the extra space between driver and hatch trunk location.

 

If you are running stock run flats that is your largest contributor to road noise. Replace those before you start doing anything else

 

Back in my construction day did some consulting work for a company out of California that had some very good acoustical products. They got bought up, have different name but still have the products. Have always thought about getting some Quiet Coat. It is expensive but the Navy uses it on their ships to minimize sound on their ships and the federal spooks use it on their rooms that they don't want people to hear what is going on.

https://www.quietrock.com/products/quietcoat

 

+1000 ^

 

First replace the runlets, that will remove more than 50% of your road noise.

Then see how much deadening you want.

Roxul needs at least 6 inches of thickness to be effective. (I know from studio experience)
Closed cell foam is only good for high frequencies, not low rumble. (Same studio experience)
Mass loaded vinyl is expensive, and you make a mess with green glue. (Studio experience again)

Its a moving automobile, also you can't get every square inch.

Find a Butyl based product like Dynamat. Its your best bet.
Dynamat is Butyl based and 4 times the price of no name brand.
Find a quality no name brand, Butyl is Butyl.
Its the Monster Cable fallacy, OFC copper is OFC copper.

 

Don't most of the sound deadening material add tons of weight? Not something you really want to do with a car.

 

Yeah, I have the 16" stock all-season Pirelli, and I only have 11k miles on the car so I don't want to replace the tires yet. But when time comes I'll definitely replace it to a non-run-flat tire. By doing the noise treatment, when I replace the tires next time, it'll be even more quieter.

I did put some Dynamat-like product (butyl based) behind the door panels, some pieces on the truck sheet metal, some on the rear sidewalls where my hands can reach by just opening the soft covers for rear lights access, but I don't know whether it helped or not because it wasn't that much to start with. I read you only need to place it in strategic places to stop steel panels resonating, and that's what I did.

I was thinking I may be able to cut the Roxul to 1" thick shapes, but does it really need to be 6" thick? I'm imagining it would be like wool batt, but I have no experience with that product so I don't know. I read that Hyundai Elantra diesel version in Korea have some kind of additional padding behind the plastic trim under the steering wheel, above the knee area to help reduce noise. I wanted to put 1" thick padding of Roxul or whatever in places with a gap.

I've read about closed cell foam - at 1/8" or 1/4" thickness, it is only used to decouple the MLV from sheet metal. If it is good at absorbing high frequency, maybe I can stuff it in inside the roof liner to block wind noise without taking too many things apart. Any recommendations on alternatives for the roof or what I should use as filling material between plastic panel and a lot of void?

I noticed taking out the rear seat is very easy, do you guys think it's worth covering the panels under the rear seat with Dynamat-like product and add CCF+MLV? It looks like the seat cushion itself is made of dense rubber type foam which would absorb noise and since it's stiff it doesn't really need Dynamat there.

I don't mind the added weight if I can quiet down the car. Even if I use up the whole roll of MLV, it's just 56 lbs for the 45 sq-feet roll.

 

I'm not adding anything that's going to increase weight. I added enough weight myself when I quit smoking.
I didn't buy the Mini expecting a great sound stage experience. I sunk a small fortune into my 2500HD Suburban including sound deadening. I won't add that extra weight to a car that I bought for performance/handling. If road/wind noise gets annoying I just turn up the volume on the HK system. Problem solved. Just my.02

 

I don't get the weight thing. Don't you ever take a passenger? Do you make them weigh in before getting in the car? Go shopping, only buy bags of leaf lettuce as they light enough to take in the car? Marshmallows, no melons however.

I'm just making fun, but seriously I think the weight issue is given too much weight.

 

Check out this site: https://www.sounddeadenershowdown.com/ They have some good technical information on how to quiet a vehicle. They have their own genericized products but you can at least get educated on what works, and what doesn't work, and for what frequencies. Interesting tidbit: according to them, you only need to "cover 25% of the surface distributed over the central 50%-75% of the panel" so that is a nice to not have to completely cover every possible surface -- saving time, money, and weight. I bet Dynamat won't agree as they'd be losing money.

 

Yeah, I checked out that site and tons of other sites as well, all couple years back. It is educational. That's why I only placed the butyl sticky tiles on specific areas only.

I may just put up all the useful links I found in the OP so that other people knows that they are there. I was hoping I can get some feedback specific to the modern MINI - F series, with real world experience.

 

Out of curiosity are you taken any sort of before/after measurements to see if any of this is helping? You should get a decibel meter or something, drive the same road at the same speeds and see how the materials impact interior noise.

 

I haven't really measured the db. The time I noticed a difference was when I stuffed the rear left and right side of the light access area with some kind of sheet of packaging foam it made a difference. If you look in that area, it's just hollow and completely open to the interior. I think MINI wanted drivers to hear the noise. On the door panels, they actually have good noise dampening stuff on the outer wall, so I don't know how or if I should tackle the door. That's why I wanted to try something like Roxul stone wool batt to try stuffing the cavities. 3M Thinsulate 600 seems too expensive as I would have to spend at least $150 for that stuff, and I don't think it would be that effective as a noise absorber.

 

There are some electronic devices in those areas, at least on the S model, like amp, etc. Not sure stuffing them with foam is a good idea.

 

Have you thought about disconnecting the engine sound amplifier?

 

Good idea. Try coding out the ASD.

 

hp79 has a Justa MINI, no ASD to code out. ASD doesn't make the road noise louder, it actually helps cover it up.

 

There are iPhone apps that do this. They are remarkably accurate; Apple calibrated their mics pretty well. I'm fond of "Audio Tools":
https://itunes.apple.com/us/app/audi...325307477?mt=8

If you only care about raw SPL then the same developer's SPL Meter Lite is the way to go:

https://itunes.apple.com/us/app/spl-...226019166?mt=8

 

Studio Six's SPL meter is "relatively" close to a true meter.
Good enough for before and after readings.
Measure at C weighted slow.

 

Studio Six or Audio Tools can be close enough, especially with a better outboard mic. I have had surprising success with this:

http://www.daytonaudio.com/index.php...icrophone.html

 

Did the back half with dynamat. Put in a remus exhaust and it got a little loud in the F55, especially since I use it to haul around a toddler few times a week. Made a pretty big difference in noise level, but still not to the level of a luxury vehicle. Probably added 20ish pounds and got it done over several days working on it 2-3 hours a night. Biggest PIA was working in a small area and my back took a beating, but taking everything apart was relatively easy.



Never took pictures of the completed product though...

 

Why didn’t you do any foam + MLV layer while at it? That’s supposed to be the major barrier. Dynamat is just for reducing vibration on the hollow sounding areas. You can try to make layers of it to act like MLV but it’s waste of money.

 

This is only my second car. My first, that I owned for 14 years, was a 2000 Lexus RX300.

My Mini is my dream car, and holy it is loud inside. I still want to put an exhaust on her though.

 

I still have MLV and CCF in transport, but I did get the UltraTouch Radiant Barrier so I went to Homedepot and bought 3M 77 Spray glue. I worked on the headliner for about 5 hours straight, trying not to break anything. When I dropped the headliner, it was a shock when I saw there's actual card-board mounted on the ceiling. I only took picture of the cardboard after placing a few butyl-aluminum backed vibration dampers. After that I cut the radiant barrier to fit front and back, and also some more extra to make up for the dead space. It was a very time consuming job. After everything, my roof now feels much more dense and no more egg crate feel from the headliner. I didn't take any picture, and didn't do any measurement on noise. The car is parked in the garage and I'll probably drive it once I'm done with doing the floors, sides, and doors with CCF+MLV and extra radiant barrier where applicable. Worst case, I will end up with much less rattles in the car since I'm also looking everywhere for possible rattles while panels are out.